SSS 2012-06-06（在线收听）

 Some dinosaurs were really huge, and now we may have a better way to estimate just how heavy these giants were. Researchers have developed a method to weigh dinosaurs based on laser scans of their skeletons. The study is in the journal Biology Letters. Looking at a bare human skeleton, how would you guess wether its owner was chubby or svelte? If you calculated how much space the fully-fleshed body occupied, you could multiply that volumn by tissue density to find the weight. Researchers laser-scanned 14 modern mammal skeletons to create digital models of each body. These 3-D models were unrealistically scrawny, with skin streched tight ove the bones. But their undersized volumns were consistent, measuring is 21% less than the actual animals. Based on the same information, researchers scanned Giraffatitan bones, added 21% to the digital model's volumn, and then calculated the dinosaur's weight---about 51,000 pounds. The technique could become the preferred way to estimate mass based on skeletons, improving our understanding of how extinct species lived and moved, and helping paleontologists make earth-shaking discoveries.